Method for making wire drawing dies



June 17, 1947. NQBORNE 7 METHOD FOR MAKING WIRE DRAWING DIES I Filed Aug. 17, 1945 IN VEN TOR.

Patented June 17, 1947 Noah Borne, Fort Wayne, Ind., assignor to Fort Wayne Wire Die Company, a corporation of Indiana Application August 17, 1945, Serial No. 610,953

3 Claims.

, 1 This invention relates to improvements in a method for making wire drawing dies wherein a refractory stone, such as a diamond, is firmly confined in an encasement, formed of hard metal,

in a definite position therein, the purpose being to resist expansion of the tone after it has been pierced, dressed and placed in use, thus to prevent fracture thereof.

Commonly, refractory die bodies are encased in a metallic structure initially formed of parts for locating the body in a definite position in the encasement while the structure is heated and plastic, and subsequently-force is applied to one of the parts axially while the other part is laterally constrained, in order to envelop the die body interposed therebetween, the parts of such structures having been variously shaped to facilitate envelopment of the die body. In the instant invention there is provided means by which one of the parts is locked relative some other at a point above and more or less remote from the encased die body, locking engagement being established without causing the die body to shift its position where initially situated during assemblage of the die body and the parts by which it is encased.

An object of the invention is to initially form the parts of which the die casing is made, so

thatwhen the parts and the stone to be encased therein are assembled, heated to a suitable temperature, and then subjected to high pressure while the casing is partially confined, said parts become permanently interlocked and the stone completely and firmly enveloped by the parts.

Another object of the invention is to afford a simple method of confining a die body within an encasement therefor in such manner that location of the axis of said body after-confine ment therein may readily be located.

Other objects and advantages of the invention appear in the following description.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which:

Fig-1 is a side elevational view of an investment plug that forms part of an encasement for a die body, aportion thereof being in section;

Fig. 2 is a side elevational view of a block forming another part of the encasement, a portion thereof being cut away;

Fig. 3 is a side elevational fragmentary view showing an assemblage of the investment plug, encasement block, a die body disposed in the block, and apparatus used in processing the compact, parts being in section;

Fig. 4 is a similar fragmentary side elevational view of the structure shown'in Fig. 3, the parts appearing as in an advanced stage during the processing; and

2 Fig. 5 is a side elevational view, partly in section showing the compact constituted of the investment plug, encasement block and the die body in relative arrangement as when in readiness for the operation of piercing thedie body.

The invention consists of a hard metallic encasement formed of two separate parts, united together, and in which is enveloped a refractory die body, such asa diamond, that is subsequently pierced and dressed suitable foruse as a wire drawing die, and the method by which the parts of the encasement are intimately interlocked to confine the refractory body centrally within the encasement.

One of the members or parts of the encasement consists initially of an investment plug 8,

cylindrical in form, provided with an annular stantially greater diameter than that of the plug,

and has formed therein a pocket I U, shaped to receive therein the plug 6, there being formed in the block at the bottom of the pocket, concentric with the axis thereof, a depression or seat II.

The plug and the block are made of similar metal, or an alloy having the characteristics of great resistance under stress of internal pressure and susceptible to reshapement when heated and subjected to compression as in the usual practice. In forming the compact the refractory die body 12 is placed within the pocket Land seated in the depression H, after which the plug is inserted into the pocket onto the die body. This assemblage is first heated to a point where the plug and blockbecome more or less plastic, and then is bodily deposited on a bed-plate I3 within a retaining ring l4 superimposed thereon. While the assemblage is hot and plastic, a ram I 5, cylindrical in form and of greater diameter than that of the plug, of less diameter'than that of the block and disposed concentric therewith, is forced by any suitable means (not shown) downwardly upon the plug and block with s'ufiicient force to cause displacement of the heated metal, whereupon the die body becomes tightly enveloped by the metal of the plug and block, and that portion of the block surrounding the plug adjacent the recess, by pressure derived from the ram, be-

comes extruded into the recess so that, upon 0001-. .ing, the block and plug are intimately locked Preliminary to the piercing and dressing operation, concentric tapered orifices l6 and I! are the piercing and dressing operations that are ordinarily applied in finishing the die.

By proportioning the investment plug and the;

block so that when the die body, plug and blocli are-initially assembled,.the tops of the plugs and q block then lie substantially in the same horizontal plane, and subsequently applying compressive force downwardly with the ram simultaneously to the plug and that adjacent region of the block encompassing the'plug while the assemblage isheated to a plastic state and laterally.

confined within the encompassing retaining ring, the die body thereupon is completely enveloped in a. definite position, the metal of the block is extruded into and completely fills the annular recess of the plug, and upon subsequent cooling of the assemblage the plug and block are thereby interlocked and shrunk about the die body and fracture thereof substantially averted.

What I claim is: L

1. The method of forming a wire drawing die consisting of emplacement of a refractory die body in a chambered metallic block, insertion into the chamber of the block a=metallic investment plug having a peripheral annular recess located between its ends, the top thereof being substantially flush with that of the block, heating the en-- casement to a plastic state, then forcefully applying a ram against the top of the plug and a substantial encompassing portion of said block, whereby to firmly imbed the die body between the plug and adjacent wall of the block and extrude the wall of the block into said recess to interlock the investment plug and block.

2. The method of forming a. wire drawing die in which a refractory die body is confined in a chambered metallic block by a metallic investment plug having a peripheral recess, initially by is exposed the corresponding polar axial exfitted into the chamber of said block, heating the assemblage of the block, die body and invest ent plug to render the blocli and plug plastic, then.

simultaneously compressing the'plug and the adjacent portion of the block that encompasses the plug, by force, whereby to firmly imbed said die I body between the plug and block and extrude the wall of the block into said recess, thus to interlock the investment plug and block.

a 3. The method of encasing a refractory die body consisting of preforming a metallic block to have an axial pocket in one end thereof and an investment plug with a peripheral recess between its ends, depositing adie body concentrically within the pocket, inserting said plug into the pocket, confining said body therein, heating the assemblage of the block, body and plug while confined within; a retaining ring on a base, and then applying force with a ,ram axially alined with the assemblage concurrently to the plug and a substantial portion of the block that encompasses the plug, the arrangement being such as to cause extrusion of the block into the recess of the plug while the block and plug are both under stress applied by the ram. NOAH HORNE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

